Electric switch



Aug. 20, 1929. w, SCOTT 1,725,106

ELECTRIC SWITCH Filed Oct. 15, 1926 4 Sheets-Sheet 1 Will/am MScoff ATTORNEY I Aug. 20, 1929. w. M. SCOTT I ELECTRIC SWITCH Filed Oct. 15,1926. 4 Sheets-Sheet FIG 2 INVENTOR I/Wl/iamM Scoff B ATTORNEY Aug. 20,1929. w. M. SCOTT ELECTRIC SWITCH Filed Oct. 15, 1.926 4 Sheets-Sheet 358 FIG. 3

H n w INVEN TOR VVi/Ifam MScoff A TTORNEY Aug.20, 1929. I WMS OTT1,725,106

ELECTRIC SWITCH Filed Oct. 15, 1926 4 Sheets-Sheet 4 INVENTOR \M/liamMSco/f Y AMA @142 .v A TTORNE UNITED STATES PATENT OFFICE.

WILLIAM M. SCOTT, OF TREDYFFRIN TOWNSHIP, CHESTER COUNTY, PENNSYLVANIA.

ELECTRIC SXVITCH.

Application filed October 15, 1926.

My invention relates to electric switches or circuit breakers.

In accordance with my invention, in response to partial or completede-energization of an elect-ro-magnct, as, for example, an underload ornon-voltage magnet, any suitable switch tripping mechanism is actuatedby the electro-magnet armature as it moves from normal to abnormalposition under the mflu ence of suitable biasing mechanism, as a helicalspring, the armature thereafter returning to normal posit-ion prior tooperation of the tripping mechanism to reset the switch incircuit-closing position.

Further in accordance with my invention, the aforesaid electric switchor circuit breaker comprises a movable contact member and a winding orelectro-magnet connected across the circuit to be controlled, thearmature of the electro-magnet being biased to coacting position withrespect to its winding for controlling departure of the movable contactmember from circuitclosing position, and for controlling the aforesaidelectro-magnet there is utilized a switch connected across the circuitto be controlled, which switch, with the circuit breaker in open orabnormal position, is closed prior to the application of a force to thearmature tending to move the same from normal position with respect toits winding.

My invention resides in the features and details of construction of thecharacter heroinafter described and claimed.

For an illustration of one of the forms my invention may take, referenceis to be had to the accompanying drawings in which:

Fig. 1 is a side elevational View of an electric switch constructed inaccordance with my invention and shown in circuitclosing position.

Fig. 2 is a front clevational view of the structure shown in F ig. 1.

Fig. 3 is an enlarged plan view of the electro-magnet armature and themechanism associated therewith.

Fig. 41 is a side elevational view of the structure shown in Fig. 3.

Fig. 5 is side elevational view of the structure shown in Fig. 4 butwiththe parts in another position.

, Fig. 6 is an end elevational View of the latch. tripper.

Serial No. 141,722.

Fig. 7 is a schematic View illustrating one form of circuit connectionwhich may be utilized with the circuit breaker described herein.

Referring to the drawings, a base 1 of slate, marble, or other suitableinsulating material, has secured thereon the main terminal blocks 2 and3 with which electrical communication is afforded through the heavycurrent conducting studs 4. Adapted to bridge and electrically connectthe terminal blocks 2 and 3, and thus close the circuit, is the movablecontact member 5 which is preferably a laminated bridging member and assuch, particularly when very heavy currents are carried thereby, is astiff spring which is more or less compressed when in the circuitclosing position shown in Fig. 1.. member 5 is secured upon the arm 6pivoted to the housing 7 at S. The intermediate metallic shunt contact 9and the movable shunt carbon contact 10 are also carried by the pivotedarm 6, and engage respectively the stationary metallic shunt contact 11and the stationary shunt carbon contact- 12. Vhen the member 5 separatesfrom the main terminal blocks 2 and 3, the current is shunted throughthese shunt contacts which open in succession, the final are takingplace between the carbon contacts 10 and 12.

The operators lever 13 having a hand grip 14 is pivoted at 15 to thehousing 7. Pivoted to the inner end of the operators lever 13 at 16 is alink 17, to whose other end there is pivoted at 18 a pair of spacedlinks 19. To the other end of links 19, at 20, is pivoted the arm 6.Pivoted at 18, independently of the links 17 and 19, are the links orlevers 21 pivoted at their inner ends at 22 to the housing 7. The link17, which may be considered as bifurcated or having two side arms, isprovided with a surface 17A adapted to engage the surface 13A on theoperators lever 13 as shown in Fig. 1., the engagement of these surfacespreventing the over travel of the toggle comprising the links 13 and 17,the end pivots being 15 and 18. and the intermediate pivot is 167 Uponthe lever 13 is provided a buffer 23 adapted to be engaged bv the link19 to cushion the same and attached parts when the circuit breakerreaches full open circuit position. 1' second toggle iscomj'irised ofthe li'iilt' 21 and 19, the end ji i 't ts being 22 The movable contactand 20, and the intermediate pivot is 18. As shown in Fig. 1, the pivot20 does not reach the imaginary straight line joining the centers of thepivots 22 and 18 but approaches so close thereto that a toggle actionoccurs.

Qne or more springs S is or are connected at one end to the pivoted arm6 and at its other end to the pivot 16 forming ajomt between the togglelinks 13 and 17. lVith the parts in the position shown in Fig. 1 thespring S is under tension. When the parts are in open circuitposition,=the switchor circuit breaker may be closed by grasping thehandle 14 and rotating. the operators lever 13 in a clockwise directionabout the pivot 15. In so doing, the closing force is transmitted fromthe link-13 through the link 17 to the pivot 18 which rotates the pairof levers or links 21 in a counter-clockwise direction about pivot 22.This rotation of links 21 is accompanied by a transmission of force fromthe said links through the links 19 to the pivot 20 causing acounter-clockwise rotation of the arm 6 about its pivot 8, thus bringingthe bridging member 5 closer and closer to the ter minal blocks 2 and 3.VJ hen the stiif spring contact 57 engages the main contacts 2 and 3, itstrongly opposes further movement. due to its spring characteristics.When this first contact position is reached, the toggles are almost inthe position shown in Fig. 1, that is, both toggles are nearlystraightened out so'that they are exerting nearly their maximum force indirections determined'by im aginary straight lines joining theirendpivotsr That is to say, the toggle 13, 17 is exerting almost its maximumforce upwardly on the pivot18, as viewed in Fig. 1'; and the toggle 19,21is exerting almost its maximum force toward the left on pivot 20 and,therefore, upon the contact member 5. A further movement of theoperators lever 13 is, as before stated, resisted by the spring of themember 5. But the toggles arenow in the position where they are capableof exerting their practically great est thrusts and, in consequence, anoperator is enabled by the further movement of the lever 13 to bring thecontact member 5 firmly and securelyinto engagement with the terminalblocks 2 and 3 by slightly deflecting and bending the still spring 5.The parts have now attained the position shown in Fig. 1 and'are'restrained or latched in that position by the dog or latch member24 pivoted loosely on the pivot 16 and thrusting at its lower left handend 25, Fig. 1, against the roller 26, pivoted to the housing on pin 27.The latch 24 is thus under compression and prevents the collapse of thetoggles and the opening of the switch or circuit breaker.

Mounted on the basal adjacent one side of the mechanism described above,Fig. 2, is a winding'28 having a core 29 disposed therewithin. Coactingwith winding 28 and core 29 are the pole pieces 30 having pole tips 30*.Extending upwardly from .each side of the left hand pole piece 30, asviewed in Figs. 1, 4 and 5, is a plate 31, Fig. 2, said plates receivinga pin or member 32 on which is pivoted the armature 33 from which rises,adjacent its free end, the projection 34 to which is secured one end ofa helical spring 35 or the like, whose other end is suitably secured toa stop member 36 whose legs 37 are pivoted on the pin 32. Movable withand preferably formed integrally with member 36, 37 is an arm 38 inwhose lateral extremity 39 is secured a pin 40 adapted to extend througha slot 41 in a link 42. In the other end of link 42 is mounted a pin 43which extends through a spacing collar 44 and is connected to a member45 mounted on and movable with link 21.

Pivoted to the pin 27 are the lugs 46 of a dog or latch tripper 46, Fig.2, herein shown as comprising a lateral arm or member 47 and a trippingmember 48. As illus trated in Fig. 2, arm 47 is disposed in part in thepath of movement of armature 33 while member 48 normally is in positionto engage the latch 24. Pivoted at 49 on the arms 50 extending laterallyfrom base 1 is a conductive member or link 51 whose end removed frompivot 49 is provided with a slot 52 through which passes the reduced end53 of a rod 53 mounted on and movable with the member 54 secured to themovable contact member 5 and formed of suitable insulating material.Secured to and extending laterally from the base 1- are the members 55and 56 formed at their ends with contact members 57 spaced apart adistance corresponding with the width of link 51. In the example shown,the members 55 and 56 are formed-of suitable conductive material and aredirectly in electrical communication with their respective contactmembers 57.

Apparatus of the character herein described is especially adapted foruse as a nowoltage control device. As one example of a system with whichthe herein described apparatusmay be associated, there is indicated inFig. 7 the line conductors L and L traversed by current from anysuitable source, not shown. Connected in se ries with the terminalblocks 2, 3 and across the line L, L is any suitable load herein shownas a motor M. Likewise connected across the line is the coil 28, thecontact members 57 being included in this circuit.

The operation is as follows:

During continuance of a voltage across the line of sufiicient magnitudeto maintain coil 28 at'a degree of energization holding armature 33 incontact [with the pole tips 30 against the retractive force of spring35, the parts remain in circuit closing position, as shown in F ig. 1;that is, with the contact member 5 closed upon the terminal blocks 2 and3.

However, should the voltage across the line drop sufficiently, spring 35overbalances the magnetic attraction of coil 28 and withdraws armature33 from pole tips 30*, the armature at its free end engaging lateral arm47 on latch tripper 46 to rotatethe same in counterclockwise direction,Fig. 1, whereby trip member 48 slightly moves the dog or latch member 24in a clockwise direction, Fig. 1. This allows the bridge 5 and springs Sto collapse the toggles and the circuit breaker parts fly to opencircuit position. \Vhile moving to open circuit position, link 42 movesdownwardly, Fig. 1, and arm 38 and stop member 36 move in a clockwisedirection about point 32, Figs. 1 and 4, whereby the tension of spring35 is relaxed and, as the circuit breaker parts reach open position, thearmature 33 under the influence of gravity moves to normal position uponits pole tips 30, Fig. 5.

\Vhen the parts moved to abnormal or open circuit position as aforesaid,link 51 was rotated in a clockwise direction, Fig. 1, and withdrawn frombetween the contact members 57, thereby opening the circuit through thecoil 28.

With the parts thus in open circuit position, lever 13 may be actuatedand, as contact member 5 closely approaches the terminal blocks 2 and 3,the conductive link 51 passes into engagement with contact members 57,thereby closing the circuit through coil 28. Closure of the circuitthrough coil 28 is thus effected as link 42 is moving upwardly, Figs. 1and 4. However, due to the lost motion arrangement comprising the pin 40and slot 41, upward movement of arm 38 does not'occur until after thecircuitthrough coil 28 has been closed as stated above. After thecircuit through said coil 28 is closed, arm 38 is moved upwardly andstop member 36 is rotated in a counterclockwise direction, Fig. 1 and 4,until link 42 reaches the upward limit of its travel at which time theend of stop member 36 engages base 1. Inthis manner, spring 35 is placedunder tension, subsequent, however, to energization of coil 28.Accordingly, if the voltage across the line is of sullicient magnitudeto overbalance the retractive force of spring 35, the circuit breakerwill remain in circuit closing position. If such is not the case, spring35 will immediately move armature 33 upwardly to trip the breaker.

\Vhat I claim is:

1. The combination with an electric switch comprising a movable contactmember and means for restraining said member in normal position, of anelectro-magnet and its armature, means biasing said armature from normalposition with respect toits electro-magnet for releasing saidrest-raining means to move said contact member to abnormal position, andmeans for disabling said biasing means by the time said contact memberhas reached abnormal position.

2. The combination with an electric switch comprising a movable contactmember and means for restraining said member in normal position, of anelectro-magnet and its armature, means biasing said armature from normalposition with respect to its electro-magnet for releasing saidrestraining means to move'said contact member to abnormal position, andmeans for disabling said biasing means while said contact member ismoving toward abnormal position.

3. The combination with an electric switch comprising a movable contactmember and a circuit controlled thereby, of means for restraining saidmember in circuit closing position, means responsive to an abnormalcircut condition controlling departure of said member from circuitclosing position comprising an electro-magnet having'an armature biasedtoward normal position with respect to its elcctro-magnet, means formoving said armature from normal position with respect to itselectro-magnet, and means for disabling said last-named means beforeinitiation of movement of said contact toward normal position. a

4. The combination with an electric switch comprising a movable contactmember and a circuit controlled thereby, of means for restraining saidmember in circuit closing position, means responsive to an abnormalcircuit condition controlling departure of said member from circuitclosing position comprising an electro-magnet having an armature biasedunder the influence of gravity toward normal position with respect toits electro-magnet, means for moving said armature from normal positionwith respect to its electro-magnet, and means for disabling saidlast-named means before initiation of movemcnt of said contact towardnormal position.

5. The combination with an electric switch comprising a movable contactmember and a circuit controlled thereby, of means for re straining saidmember in circuitclosing position, means responsive to an abnormalcircuit conditon controlling departure of said member from circuitclosing position comprising an electro-magnet having an armature biasedtoward normal position wit-h respect to its electro-magnet, a spring formoving said armature from normal position with respect to itselectro-magnet, and means for disabling said spring by the time saidcontact member has reached abnormal position.

6. The combination with an electric switch comprising a movable contactmember and a circuit controlled there-by, of means for restraining saidmember in circuit closing position, means responsive to occurrence ofpredetermined drop in voltage across said circuit controlling departureof said member from circuit closing position comprising a windingconnected across said circuit and having an armature biased towardnormal position with respect to its winding, means for moving saidarmature from normal position with respect to its winding, and means fordisabling said last-named means before initiation of movement of saidcontact toward normal position.

7. The combination with an electric switch comprising a movable contactmember and a circuit controlled thereby, of means for restraining saidmember in circuit closing position, means responsive to occurrence ofpre-' determined drop in voltage across said circuit, controllingdeparture of said member from circuit closing position comprising awinding having an armature biased under the influence of gravity towardnormal position with respect to its electro-magnet, means for movingsaid armature from normal position withrespect to its winding, and meansfor disabling said-last-named means while said member is moving towardabnormal position.

8. The combination with an electric switch comprising a movable contactmember and a circuit controlled thereby, of means for restraining saidmember in circuit closing position, means responsive to an abnormalcircuit condition for moving said member to abnormal position comprisingan electromagnet having an armature biased toward normal position withrespect to its electromagnet, a'second switch controlling the circuit ofsaid electro-magnet, and means for opening said switch and disablingsaid lastnamed means during movement of said contact toward abnormalposition.

- 9. The combination with an electric switch comprising a movablecontact member and a circuit controlled thereby, of means forrestraining said member in circuit closing'position, electro-magneticmeans responsive to an abnormal circuit condition comprising an armaturecontrolling departure of said member from circuit closing position,means for moving said armature from normal position with respect to itselectro-magnet upon occurrence of said abnormal condition, and meanscontrolled by said restraining means for disabling said last-named meansduring movement of said contact member from normal position.

10. In an electric switch, a movable contact member, means forrestraining the same in normal position, a movable member for actuatingsaid restraining means, an electro-magnet, an armature for actuatingsaid movable member biased into co-acting relation with respect to saidelectro-magnet, a spring biasing said armature in reverse direction, andmeans actuated through the agency of said contact membeer for decreasingthe tension of said spring during movement ofcontact member from normalposition.

11. Thecombination with an electric switch comprising amovable contactmember and means for restraining said contact member in normal position,of an electro-magnet having an armature normally biased into engagementtherewith, a member movable in response to movement of said switch toabnormal position, a spring secured to said second-named memberand'armature, and means'co-acting with said armature for effectingmovement of said switch to abnormal position.

12. The combination with an electric switch comprising a movable contactmember and means for restraining said contact member in normal position,of an electro-magnet having a pivoted armature normally biased intoengagement therewith, a pivoted member movable in response to movementof said switch 'to abnormal position, a spring connected at its ends tothe free ends of said second-named member and armature, and meansco-actingwith said armature for efi ecting movement of said switch toabnormal position.

. 13. In. an electric switch, a movablecontact member, means forrestraining the same in normal position, a movable member for actuatingsaid restraining means, an electromagnet, a second switchactuated bysaid restraining means for controlling said electromagnet, an armaturefor actuating said movable member biased into (Io-acting relation withrespect to said electro-magnet, a spring biasing said armature inreverse direction, and means comprising a lost motion device connectedto said restraining means and controlled thereby for changing thetension of said spring during movement of said contact member. p

, 14. The combination with an electric switch comprising a movablecontact member and a circuit controlled thereby, of means forrestraining said member in circuit-closing position, means for releasingsaid 'restraining means upon occurrence of an abnormal condition in'saidcircuit comprising an electro-magnet and an armature normallyrbiasedtoward said magnet, resilient means urging said armature in oppositedirection and controlled by the position of said contact member, asecond switch cooperating with said contact member for controlling thecircuit of said electro-magnet, said second switch being moved to closedposition during closing movement of said contact member, and meansdisabling said resilient means until said second switch has reached itsclosed position.

15. The combination with an electric switch comprising a movable contactmember and a circuit controlled thereby, of means for restraining saidmember in circuit-closing position, means responsive to abnor malcircuit condition for moving said member to abnormal position comprisingan electro-magnet having an armature biased toward normal position withrespect to its electro-magnet, a second switch controlling the circuitof said electro-magnet, means for opening said switch and disabling saidlastnamed means during movement of said contact toward abnormalposition, and lost-motion means for permitting closure of said switchprior to energization of said means for biasing the armature to abnormalposition.

16. The combination with an electric switch comprising a movable contactmember and a circuit controlled thereby, of restraining means formaintaining said contact member in normal position, electro-magneticmeans for releasing said restraining means comprising an armaturenormally attracted towards its magnet, resilient means acting on saidarmature and opposing the normal attraction of said magnet when saidcontact member is in normal position, and means for maintaining saidresilient opposing means ineffective from the time said contact memberis moving towards abnormal position until the same is in close proximityto its normal position.

17. The combination with an electric switch comprising a movable contactmember and a circuit controlled thereby, of restraining means formaintaining said contact member in normal position, means for releasingsaid restraining means upon occurrence of an abnormal condition in saidcircuit comprising an electro-magnet and an armature normally attractedthereto, means normally urging said armature in opposite direction, asecond switch operated by said contact member for controlling thecircuit of said electro-magnet, and means for rendering said last-namedmeans ineffective while said second switch is in open position.

WILLIAM M. SCOTT.

